1. Field of the Invention
This disclosure relates generally to a subsurface tool used in hydrocarbon wells, and more particularly to an improved cross-over tool.
2. Description of the Related Art
Hydrocarbon wells, such as oil or gas wells, frequently require that the hydrocarbon-bearing formation be fractured to adequately produce hydrocarbons from the well. Fracturing cracks the formation to create more surface area from which the hydrocarbons may flow. Fracturing generally occurs after the well has been drilled, casing has been placed, and various completion tools inserted into the well. Slurry containing fracture propping agents may be pumped into the fractures or cracks to prop the cracks in an open position. A completion assembly having one or more screens may be placed in the well bore to allow hydrocarbons to flow into production tubing and up to the well surface without allowing the proppant, sand and other debris from the formation to flow into the tubing.
Typically, propping agents, i.e., proppants, are pumped through a central flow path, such as a tubing string disposed in the casing, and diverted to an annulus existing between the completion assembly and the casing to fill the annulus in the region of the screen. This flow path may be reversed to wash out to the surface excess proppant and other debris remaining in the system.
Diversion of the flow from the central flow path through the completion assembly and into the annulus is usually effected by a service tool assembly, such as a cross-over tool. Typically, a cross-over tool is positioned in the completion assembly so that the slurry is diverted (or crossed over) from the central flow path of the tubing string into the annulus around the screen and into the formation. The reversal of flow may be accompanied by repositioning the cross-over tool to a reversing position, which creates a flow path down an upper portion of the annulus and back up the central flow path.
In the reversing position, a valve is actuated to close off and seal the fracturing ports in the completion tool assembly. Often times, this valve is a sleeve assembly located below the fracturing ports when the ports are in the opened position. Thus, to close the ports in the completion assembly, the sleeve is typically moved or actuated in an uphole direction. It will be appreciated that when the valve is located below the fracturing ports, debris, such as proppant from the fracturing slurry that doesn't make it to the annulus or sand from the formation, may become lodged about the valve and hamper its operation or effectively prevent its operation. In many cases, reversing the flow will not wash out all of this debris. The remaining debris may cause the completion fracturing port valve to require excessive actuation force or it may cause the valve to be uncloseable.
In this context, this application discloses and claims an improved cross-over tool and method of use.